Openldap log files not deleted

We had to move our Zimbra install directory today and discovered that there were a massive amount of log files in the openldap-data directory. In total they were 7GB and all dated from the last update onwards. For some periods there wer 10MB logfiles generated every minute.

Now normally ldap should delete old logfiles or is there a specific reason against it?
If not then adding

Code:

set_flags DB_LOG_AUTOREMOVE

to DB_CONFIG (probably) in $zimbra/openldap/etc/openldap should take care of the problem.
The probably generated DB_CONFIG file in $zimbra/openldap-data is empty here.